Hey future scientists! 👋 Today, we're diving into the fascinating world of pregnancy testing and the hormone hCG. Trust me, it's like the 'Avengers' but for biochemistry. Ready? Let's roll! 🚀

Human chorionic gonadotropin (hCG) is a protein, not a small one but medium-sized. Think of it like the middle child of proteins.

• Key Role: Produced by embryo's trophoblast cells, starting at the blastocyst stage.
• Real-world example: You know how a car engine needs fuel to run? Similarly, a pregnancy needs hCG to sustain. No hCG = No pregnancy.

• It keeps the pregnancy from falling apart by maintaining the corpus luteum for the first 10 weeks.
• The corpus luteum secretes progesterone, which basically keeps the uterine lining comfy for the baby.
• After 8-12 weeks, the placenta takes over and starts secreting progesterone.

🍕 Pizza Analogy: Imagine the corpus luteum as your first pizza slice and the placenta as the whole pizza. Initially, one slice satisfies you, but eventually, you need the whole pizza to keep you happy. That's progesterone for you!